Water-based lubricating coating agent for metal material, surface-treated metal material, and method for forming lubricating coating for metal material

Abstract

The water-based lubricating coating agent having pH of 2.0 to 6.5 for a metal material is obtained by blending: at least one lubricating component other than black-based solid lubricants; and at least one chemical conversion component selected from the group consisting of a phosphoric acid compound, an oxalic acid compound, a molybdic acid compound, a zirconium compound, and a titanium compound, the concentration of the lubricating component is 5 mass % or more in mass ratio to the total solid content mass in the lubricating coating agent, and the concentration of the chemical conversion component is 0.3 to 8 mass % when the total mass of the lubricating coating agent is regarded as 100 mass %.

The invention claimed is: 
     
       1. A water-based lubricating coating agent for a metal material, the agent having pH of 2.0 to 6.5, which is obtained by blending:
 at least one lubricating component, that is not a black-based solid lubricant, comprising carrier particles (C); and 
 a chemical conversion component that comprises at least one of the group consisting of a primary sodium phosphate, oxalic acid, and ammonium molybdate, 
 wherein a concentration of the lubricating component is 5 mass % or more in mass ratio to a total solid content mass in the lubricating coating agent, and a concentration of the chemical conversion component is 0.3 to 8 mass % when a total mass of the lubricating coating agent is regarded as 100 mass %, 
 wherein the carrier particles (C) comprise a lipophilic lubricating component (A) and a cleavage solid lubricant (B), 
 wherein the lipophilic lubricating component (A) comprises at least one of the group consisting of plant oil, mineral oil, and synthetic oil, 
 wherein the cleavage solid lubricant (B) comprises a layered clay mineral (B2), 
 wherein the layered clay mineral (B2) comprises at least one of the group consisting of kaolinite, talc, and mica, and is 30 μm or less in average particle size, and 
 wherein the carrier particles (C) are particles that include the lipophilic lubricating component (A) between particles of and/or between layers of the layered clay mineral (B2). 
 
     
     
       2. The water-based lubricating coating agent for a metal material according to  claim 1 , wherein the lipophilic lubricating component has a solubility parameter (SP value) of 10 or less. 
     
     
       3. The water-based lubricating coating agent for a metal material according to  claim 1 , wherein the layered clay mineral is 40° or more in water contact angle. 
     
     
       4. The water-based lubricating coating agent for a metal material according to  claim 1 , wherein an aspect ratio is 3 to 150 in a cross section of the layered clay mineral. 
     
     
       5. The water-based lubricating coating agent for a metal material according to  claim 1 , wherein in the carrier particles, an inclusion amount of the lipophilic lubricating component is 5 mass % or more in mass ratio to a total mass of the carried particles. 
     
     
       6. The water-based lubricating coating agent for a metal material according to  claim 1 , wherein the layered clay mineral has Mohs hardness of 2 or less. 
     
     
       7. The water-based lubricating coating agent for a metal material according to  claim 1 , further comprising, as a binder component for a lubricating coating, at least one selected from the group consisting of a water-based inorganic salt, a water-based organic salt, and a water-based resin. 
     
     
       8. A surface-treated metal material, wherein a coating formed on a metal material surface by using the water-based lubricating coating agent for a metal material according to  claim 1  comprises two layers of a chemical conversion coating on the metal material surface, and a lubricating coating on the chemical conversion coating, and as dried coating amounts, the chemical conversion coating for a lower layer is formed to be 0.1 g/m 2  or more, whereas the lubricating coating for an upper layer is formed to be 0.5 g/m 2  or more. 
     
     
       9. A method for forming a lubricating coating for a metal material, the method comprising a contact step of bringing a metal material into contact with the water-based lubricating coating agent for a metal material according to  claim 1 . 
     
     
       10. The water-based lubricating coating agent for a metal material according to  claim 2 , wherein the layered clay mineral is 40° or more in water contact angle. 
     
     
       11. The water-based lubricating coating agent for a metal material according to  claim 2 , wherein in the carrier particles, an inclusion amount of the lipophilic lubricating component is 5 mass % or more in mass ratio to a total mass of the carried particles. 
     
     
       12. The water-based lubricating coating agent for a metal material according to  claim 2 , further comprising, as a binder component for a lubricating coating, at least one selected from the group consisting of a water-based inorganic salt, a water-based organic salt, and a water-based resin.